In 1941 the Park Service hired Adams to photograph the parks for a mural in the Interior Building. The war stopped it, the mural was never made, and the 226 photographs he had already taken are yours to download.

The commission was specific: a photo mural for the Department of the Interior Building in Washington, on the theme of nature as exemplified and protected in the national parks. Adams spent 1941 and 1942 on it, working through the Grand Canyon, Grand Teton, Kings Canyon, Mesa Verde, Rocky Mountain, Yellowstone, Yosemite, Carlsbad Caverns, Glacier and Zion; Death Valley, Saguaro and Canyon de Chelly; Boulder Dam, and several Pueblo communities in the Southwest. Then the war came, the project was halted, and it was never resumed.

What survives is the assignment without the deadline. The prints came to the National Archives in 1962 as series 79-AA, 226 photographs, most of them signed and captioned by Adams himself. They are in the public domain, and the National Archives Catalog serves them at full resolution to anyone who wants them — free to view, free to download, free to order as prints, no account and no licence negotiation.

The difference between this and a gallery show is that you can have them. “The Tetons and the Snake River” — the river turning through the dark conifers under a bank of weather, arguably the most reproduced landscape photograph made in America — is a catalogue record with a download button on it. So is Cliff Palace at Mesa Verde, and the snow-covered apple tree below Half Dome, which is the sort of small picture that never makes the posters and is better than most of the ones that do.

It is also worth reading Adams on why he kept doing it after the money stopped. He never quit photographing the parks or arguing for them, and in 1983 he was still counting: “Only two and a half percent of the land in this country is protected… we are having to fight to protect that small two and a half percent.”

One caveat, stated precisely because vagueness here costs people money. Not every Adams image at the National Archives is unencumbered. Eight Yosemite photographs held in a different series, 79-G, may still be under copyright. The 226-image 79-AA series is the clean one; if you stray outside it, check the Archives’ own copyright and permissions guidance before you print anything at scale.

The mural was never built. The best possible consolation is that the pictures for it ended up more available than any mural could have been.